Go to Setup > Picklist Value Sets
These are the Global Picklist setup global picklists set up in the Org.
...
Attendance Status
The list of options for Attendance Status - used in Event object Session Student records for student attendance; and Day Attendance Attendance Status.
...
Days
...
Grade Levels
These Grade Levels are based on the Edval etz file.
...
Periods
These Periods are based on the Edval etz file.
...